Species-related variations in the sensory-efferent functions mediated by the capsaicin-sensitive sensory neurons at urinary bladder level: relation to bladder content of substance P-like immunoreactivity.

Noticeable species-related differences exist with regard to the function mediated by the capsaicin-sensitive neurons in the urinary bladder. Systemic capsaicin desentization increased bladder capacity in rats and guinea-pigs and reduced voiding efficency in these latter. Urodynamic paranmeters were unaffected in hamsters. Capsaicin increased plasma extravasation in the lower urinary tract of rats, mice and guinea-pigs, but not in hamsters. SP-LI was detected in the urinary tract of rats, guinea-pigs, rabbits and mice but not hamsters. Bladder SP-LI was depleted by systemic capsaicin desensitization in in rats, mice and guinea-pigs.